Return-Path: Message-ID: <41A67548.90805@dark-reality.de> From: Lars Grunewaldt MIME-Version: 1.0 To: bluez-devel@lists.sourceforge.net Subject: Re: [Bluez-devel] more encoder stuff References: <41A56774.1000308@xmission.com> <20041125071423.10e449c3.henryk@ploetzli.ch> <1101365484.7538.74.camel@pegasus> <20041126000655.1a762210.henryk@ploetzli.ch> <1101425014.6465.39.camel@pegasus> In-Reply-To: <1101425014.6465.39.camel@pegasus> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: bluez-devel-admin@lists.sourceforge.net Errors-To: bluez-devel-admin@lists.sourceforge.net Reply-To: bluez-devel@lists.sourceforge.net List-Unsubscribe: , List-Id: BlueZ development List-Post: List-Help: List-Subscribe: , List-Archive: Date: Fri, 26 Nov 2004 01:14:00 +0100 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Marcel Holtmann wrote: | Hi Henryk, | | |>>The MAD library (www.underbit.com/products/mad/) is using fixed-point |>>integer computation. Do you think it is possible to do the same thing |>>for SBC? Will it give us some extra performance? |> |>Unfortunately I'm not familiar with fixed-point arithmetics, especially |>with how to handle multiplication. So if anyone who has done this before |>would step forward ... |> |>Well, I did some naive tests: I probably did something wrong, but I'm |>not seeing any significant difference between floating point and fixed |>point (that is: integer). For multiplication the difference is not |>noticeable (1.38s vs. 1.36s in my test program) and for addition it is |>not that big (0.77s vs. 0.47s). |> |>I guess we'll be fine using floating point as long as there is an FPU. | | | we can optimize at any time if needed, because the SBC API should hide | this stuff. For me this sounds perfect for a diploma thesis for someone | interested in audio codec stuff and Bluetooth. *raising hand* thing is, on modern CPU you won't get much speedup with fixed point stuff, because the main advantage was eliminated by Intel when they build the pseudo-pipes into their FPU's. That's why id used floating point operations for gfx for the first time, making life for non-Pentium owners really hard. AMD also has the pseudo-pipes, and modern multiplication/devision on FPU is very fast. But of course there are still some cycles to kill in audio processing always. I'll advertise this project to my professor... cu, ~ Lars -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFBpnVHQWC6DTWkDAoRAgkgAKDAZ9hRDYGRP4sNtuJKFFu/0zcomQCgmG8v UoPSMR/LGba03dC7OsdwkUM= =vL5b -----END PGP SIGNATURE----- ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://productguide.itmanagersjournal.com/ _______________________________________________ Bluez-devel mailing list Bluez-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bluez-devel